Three servers is enough to get very good search results - if they are the right three servers.

Check that the servers are all ultrapeers - if not, manually remove them (non-limewire peers usually show up as '0.6' - you don't want these).

If your search results are still returning very few values then disconnect all the servers and reconnect (File|disconnect/connect).

These will eventually settle down on a new set of servers that may well give you better results.

If you really want lots of connections (but not necessarily better search results and almost certainly bad download speeds if you are on a slow connection) then set yourself up as an ultrapeer (you probably can't do this unless your connection is cable or better).

Mark